I saw this on Pinterest and thought it would be a perfect project for Valentine's Day! It is similar to an art therapy project I like to do with my geriatric patients. The original idea was posted here.
Cut out various heart shapes using the white paper and scissors. Then, write a special message to a loved on the heart. Give the valentine, along with the watercolors to the person. When they paint over the heart, the message written in white crayon appears.
This would also be a cool project to do in a rehab setting. Have each client write down inspiring messages, notes of encouragement, or personal affirmations, each on a piece of white paper. Then, when they are feeling down or discouraged, they can pull out one of the sheets of paper, color over it with watercolor and remember the message as a "pick me up."
You could also use this idea for a "graduation" from a program. When a person successfully completes your program, have all the other clients write down positive notes and congrats. Give the stack of white papers and a set of watercolors as a departing gift.